1. Field of the Invention
The present invention relates to a lens-fitted photo film units, by which picture frames can be designated to be printed in different formats within a filmstrip by optically recording print format data in association with each picture frame.
2. Background Arts
Lens-fitted photo film units, hereinafter referred to as film units, each preloaded with a photo film cartridge, are getting more popular as a user-friendly snap camera. The film unit has a film roll chamber and a cartridge chamber for holding a roll of unexposed photo filmstrip and a film container or cartridge shell respectively. An exposure frame is formed between the cartridge chamber and the film roll chamber. The filmstrip is exposed through an exposure aperture confined by the exposure frame, and is wound into the cartridge shell one frame after each exposure.
Since a cheap fixed-focus optical system is used as the taking lens of the film unit, the filmstrip is supported to be forwardly concave behind the exposure aperture in order to correct the curvature of the field. Therefore, the exposure frame is shaped to be rearwardly convex along the lengthwise direction of the filmstrip.
For handiness sake, the film unit is expected to be as compact as possible. Recent trend is to make the unit body thinner than the outer diameter of the cartridge shell except the cartridge chamber.
Recently, film units containing a new type photo film cartridge called IX 240 type or APS (Advanced Photo System) type have been brought into market. The IX 240 photo film cartridge can contain a leader of a filmstrip therein and advance it to the outside by rotating its spool in an unwinding direction. The standard frame exposure range of the filmstrip contained in the IX 240 photo film cartridge is 16.7 mm.times.30.2 mm.
To add amusement in the snap-photography, a print system has been provided for making photo prints in different formats, including a conventional ISO 135 standard size (C size) whose aspect ratio is about 1.5, an elongated panoramic size (P size) which is about double the ISO 135 size in length and thus has an aspect ratio of about 3.0, and a high-vision size (H size) whose aspect ratio is proximate to that of the high-vision TV screen, i.e. about 1.8. In general, the P size photo print is about 89 mm.times.252 mm, the H size photo print is about 89 mm.times.158 mm, and the C size photo print is about 89 mm.times.127 mm.
It is also known in the art to record every picture frame in the same size and record print format data for designating a print format to each frame concurrently with the exposure. According to this method, prints are made in the designated print formats from the same size picture frames by limiting the printing range of each frame to be correspondent to the designated print format.
As the aspect ratio of the IX 240 standard frame is about 1.8, i.e. the H size, a H size photo print is made from the standard frame. In this case, the C size photo print is made by limiting right and left portions of the IX 240 standard picture frame. On the other hand, a P size photo print is made by limiting upper and lower portions of the IX 240 standard picture frame.
In the film unit, the print format data is optically recorded as a dot pattern on the photo film on one margin of the picture frame. To record the dot pattern, a plurality of holes are formed through a wall portion of the exposure frame, and a data switching blade is mounted in front of the wall portion, so as to be slidable for covering or uncovering some of the holes.
Mounting such a plate to be slidable in front of the wall portion of the exposure frame can increase the thickness of the film unit. In addition, the data switching blade should be sufficiently close to the film surface so as the dot pattern to be recorded clearly enough for automatic discrimination of the dot pattern.